Piston pump for liquids



Nov. 13, 1962 J. REUTTER PISTON PUMP FOR LIQUIDS Filed March 10, 1961 INVENTOR JEAN Ls'olv REUTTEI? WW A'TTORNEY nite Claims priority, application Switzerland, Nov. 7, 1960 2 Claims. (Cl. 103163) The present invention has for object a piston pump, for liquids, which is characterized in that the piston moves in a cylinder accompanying it during a part of its stroke, in that this cylinder is integral with the movable part of a valve controlled by the piston and disposed to establish the communication between the low pressure chamber and the inside of the cylinder during the suction stroke of this piston, and between this cylinder and the high pressure chamber during the compression stroke, abutment means being provided to stop the cylinder at the two ends of its stroke.

The single figure of the accompanying drawing shows, by way of example, an embodiment of the pump object of the invention, seen in axial section.

In this example, the pump may be a fuel oil pump for a burner and its drive may be effected by an oscillating electro-magnetic motor. The driving motor could be of another type.

In the drawing, the motor not shown communicates a reciprocating axial movement to a rod 25.

The rod 25 passes through two water-proof packings 41, 42. The right-hand end in the drawing of the rod 25, indicated by 43, forms the piston of the pump. This piston slides in a cylinder 44 having at 45 radial orifices, of which only one is visible in the drawing, causing the interior of the cylinder to communicate with its exterior. The pump cylinder 44 extends to the left in the shape of a cylinder 46 of larger diameter, in which slides an auxiliary piston 47, integral with the rod 25 due to a pin 48. This cylinder 46 is provided, in its side Wall, with a hole 49. The unit consisting of the auxiliary piston of the cylinder 46 and of the hole 49 constitutes a dash-pot the function of which will be explained later.

The cylinder 44 is integral with two seats 59, 51, each disposed on one side of a fixed wall 52 separating a low pressure chamber 53 from a high pressure chamber 54. A substantial clearance is provided at 55, between the outer wall of the cylinder 44 and the part of the Wall 52 through which this cylinder passes.

The operation of this pump is the following:

In the position shown in the drawing, the piston 43 is at the left-hand end of its stroke and the seat 51 is applied against the wall 52, thus closing the communication between 54 and 53, on the one hand, and between 54 and the inside of the cylinder 44, on the other hand. If now, one supposes that the rod 25 moves to the right, the auxiliary piston 47 compresses the liquid arriving by the duct 56 and filling the cylinder 46, as well moreover as the low pressure chamber 53.

This action of the auxiliary piston 47 on the liquid which is in the cylinder 46 has for eifect to bring about the drive of this cylinder 46 and with it the cylinder 44 until the abutment 50 bears against the wall 52. After this, the rod 25 and the piston 43 continue their movement independently of the cylinders 46 and 44, the liquid which is in the cylinder 46 issuing therefrom at 49. The piston 43 therefore compresses the liquid which is in the cylinder 44. This liquid escapes from this cylinder by the holes 45 and reaches the high pressure chamber '54. At the instant when, having reached 3,953,332 Patented Nov. 13, 1962 its end position to the right, the piston 43 returns towards the left, the cylinder 46 begins to accompany this movement until the seat 51 bears against the Wall 52. From that moment, the communication is reestablished between the low pressure chamber 53 and the inside of the cylinder 44. The liquid which is in 53 penetrates into this cylinder which then fills itself until the end of the stroke of the piston, after which the operations described with respect to the compression stroke start again, and so on. It is obvious that the pump being adapted to operate at relatively high speed (for example 50 double oscillations per second), the time necessary to bring the seats 5t), 51 from the active position to the inactive position and inversely is extremely short and, consequently, negligible.

At 57 is seen the outlet of the pump. This outlet is connected to a duct 58 issuing in a chamber 59 where is the packing 42. This arrangement has for efllect that a part of the fuel oil issuing from the pump serves to ensure the lubrication of the movable members of the pump.

It will be seen that the arrangement of the seats 51 and 50, distant one from the other by an amount slightly greater than the thickness of the wall 52, constitutes a valve controlled by the piston establishing the communication by the orifices 45 between the low pressure chamber and the inside of the cylinder, during the suction stroke, and between this cylinder and the high pressure chamber, during the compression stroke, in an absolutely certain manner, whatever the speed at which the pump operates.

In a variant, instead of the cooperation between the piston 43 and the cylinder 44 taking place through the agency of a hydraulic device 46, 47, there could be provided a friction element, ensuring a partial drive, with a limited stroke, of the cylinder 44 by the piston 43, at each of the strokes of the latter.

In a variant, there could be no clearance 55 between 44 and 52. The diameter of the hole 45 would then be equal to the thickness of the wall 52 and the parts Sti and 51 would no longer operate as seats, but as abutments limiting the stroke of the cylinder 44. In this case also, one would have a valve (a slide valve according to this variant) controlled by the piston and establishing, at the desired moments, the communication between the low pressure chamber 53 and the cylinder 44, and then between this cylinder and the high pressure chamber 54.

What I claim is:

1. Piston pump for liquids, comprising a housing, a cylinder in said housing, a piston mounted for reciprocation in said cylinder, a 'wall dividing said housing into a low pressure chamber and a high pressure chamber, a first passageway between said low pressure chamber and said cylinder, a second passageway between said high pressure chamber and said cylinder, means upon said cylinder cooperating with said wall to alternately open and close said passageways, and hydraulic means cooperating with said piston and said cylinder so that said cylinder accompanies said piston along a part of its stroke until said means upon said cylinder abut said wall and limit the movement of said cylinder and stop it at the end of its stroke to establish through said first passageway the connection between said low pressure chamber and the inside of the cylinder during the suction stroke of said piston, and to establish through said second passageway the connection between the inside of said cylinder and said high pressure chamber during the compression stroke of said cylinder.

3 '4 2. Piston according to claim 1 wherein said means and said seats being spaced from one another a distance upon said'cylinder cooperating with saidwall comprises greater than the thickness of said wall.

a seat fixed upon said cylinder at each side of said wall,

said 'Wall having a hole therein separating said 10w pres- References Cit d in the file Of this patent sure chamber from saidvhigh pressure chamber through 5 UNITED STATES PATENTS which said cylinder passes with clearance, said cylinder having an orifice allowing the interior of said cylinder to 1,252,875 Ashmusefl n- 19 communicate with the exterior located between said seats, 1,514,567 ONeill Nov. 4, 1924 

